Saving Images in Databases

[NickThissen]

Quick question:

What do I do if the user decided not to choose an image?

I have an Access 2007 database that can store an image using your code, the image is optional. If the user decides not to choose an image then I don't know what to store in the database.

In the GUI I have a Picturebox that shows the image the user has chosen. They use an OpenFileDialog to choose an image location, and I then set the ImageLocation property of the PictureBox to that path.
Then, when saving, I take the Image property of the PictureBox directly as the Image object you use in your code.

But when the user did not chose an image, the Image is null.


I am using this code to load:

private Image LoadImage(byte[] picData)
        {
            Image pic = null;
            using (MemoryStream stream = new MemoryStream(picData))
            {
                pic = Image.FromStream(stream);
            }
            return pic;
        }

And I am using this code to save:

public void ExecuteNonQuery(string sql, Image pic)
        {
            if (this.IsOpen())
            {
                using (OleDbCommand cmd = new OleDbCommand())
                {
                    cmd.Connection = _connection;
                    cmd.CommandType = System.Data.CommandType.Text;
                    cmd.CommandText = sql;
 
                    using (MemoryStream stream = new MemoryStream())
                    {
                        cmd.Parameters.Clear();
                        if (pic != null)
                        {
                            pic.Save(stream, ImageFormat.Jpeg);
                            cmd.Parameters.Add("@foto", OleDbType.Binary).Value = stream.GetBuffer();
                        }
                        else
                        {
                            // what to do?
                            cmd.Parameters.Add("@foto", OleDbType.Binary).Value = new byte[] {};
                        }
                    }
                    cmd.ExecuteNonQuery();
                }
            }
            else
            {
                throw new Exception(strNO_DB_CONNECTION);
            }
        }

(The @foto parameter will always be present in the sql that I pass to this function.)

I tried various things for the value of the @foto parameter:
- null
- 0
- new byte[] {}
- simply stream.GetBuffer() as if there was a picture.

None of them work. I keep getting an exception "Parameter is not valid." on the Image.FromStream method in the Load function...

I can't simply not save it when the user didn't chose an image, because it is possible for the user to edit a record and remove the image that was previously chosen. So if I don't do anything that change wouldn't be recorded as the old image would still be in the database.


To fix this I can check if the picData array has zero length. That works when I simply store stream.GetBuffer on a new (empty) stream, but I'm not really sure if that's the 'accepted' way of doing it. What am I storing in the database in that case?